This application claims the priority of Korean Patent Application No. 2003-68333, filed on Oct. 1, 2003, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present invention relates to a method of manufacturing an antenna for a device that transmits and receives information by a wireless transmitter and a wireless transmitter using the antenna.
2. Description of the Related Art
A smart label, typically known as a radio frequency identification (RFID) tag, generally refers to a communication or information device with an integrated circuit for storing various information and an antenna for communication with an external terminal. Such a smart label is generally used for inventory control or logistic management, as electronic identification cards, electronic moneys, or credits cards, or for other communication and information handling purposes. For example, when the smart card is used for logistic management purposes, the smart card can replace conventional markings such as bar codes and is attached to an object to be identified and managed. For managing inventory or logistic information, the conventional bar codes must be brought in close proximity to a bar code reader for identification of their information. However, when using the smart card, if the smart card is placed within a recognition range of a terminal such as an RF reader, the objects having the smart card can be recognized even if the smart card is placed in a hidden location or remotely placed from the terminal. Therefore, the smart label can be more efficiently used instead of the conventional bar code system.
Smart labels can often be classified into high frequency smart labels and low frequency smart labels according to the communication method with a terminal. Communications between the terminal and the smart label are typically implemented by a radio frequency (RF) signal. As such, exchange of information utilizing the smart label system can be faster than the conventional bar code system.
In a smart label using the RF signal, an antenna is formed on a substrate of the smart label. Conventional methods for forming an antenna on the substrate typically include: etching a laminated metal layer (e.g., Cu or Al) formed on a flexible substrate (e.g., PET, PE, or PVC) using a mask with a predetermined pattern; affixing wound wires for forming the antenna on the substrate using a liquid adhesive; and depositing a thin metal element on the substrate. However, the formation method of the antenna by etching requires an increased number of processes, such as exposing and developing of the laminated substrate typically by expensive equipments and using additional resources such as a developing solution. Thus, these formation methods utilizing the etching process are generally time consuming and costly. Also, these methods utilize wires and metal depositions, and thus, are uneconomical since they have low yields. These drawbacks need to be solved for the mass production of the smart labels, especially, in view of the fact that smart labels are often discarded after a single use.
FIG. 1 is a schematic drawing illustrating a conventional smart label, and FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1.
Referring to FIGS. 1 and 2, a smart label 10 is shown, that can be used for transmitting or receiving a high frequency signal of 13.56 MHz, for instance. The smart label 10 has a chip 12 mounted on a support member 11 and an antenna 13 electrically connected to the chip 12 for wireless communications with a reader. The antenna 13 is formed on an outer surface of the support member 11, and has a loop circuit with an inner lead connected to a first terminal 14 formed on an inner side and a second terminal 15 formed on an edge of the support member 11. The first and second terminals 14 and 15 are electrically connected to each other. The first and second terminals 14 and 15 are typically connected to each other by a conductor 17 which crosses over the circuit lines of the rolled antenna 13. As shown, a liquid insulating material 16 is coated around the adjacent circuit lines of the antenna 13 and dried for preventing a short circuit of the antenna 13 by the circuit lines. The conductor 17 (such as an Ag paste) is formed on the insulating material. In particular, an Ag paste 17 is coated on the dried insulating material 16 and dried. The antenna 12 is configured in such a loop shape to allow wireless communications at a high frequency of 13.56 MHz with an external reader.
However, as described above, this conventional method of manufacturing a smart label is rather complicated and expensive.